1. Field of the Invention
The present invention relates to an organism state quantity measuring apparatus.
2. Description of Related Art
Among apparatuses for injecting insulin into an organism, an apparatus is conventionally known that measures the glucose level in an organism and controls the amount of injection of insulin according to the measured value obtained (see, for example, the publication of Japanese Patent No. 3683856). An analog signal for the measured glucose level is converted into a digital signal by an A/D converter having an integration circuit, and the digital signal is processed.
However, Characteristic values such as an electrostatic capacitance and a resistance value of circuit elements such as a capacitor and a resistor constituting the integration circuit change with time depending on the time during which the circuit elements are used and the environment surrounding the circuit elements, for example. At that time, in the case of the apparatus according to Japanese Patent No. 3683856, the output from the integration circuit changes with changes in characteristic values of the circuit elements and it is difficult to obtain an accurate measured output value.